The present invention relates to a connecting rod incorporating an energy absorber.
Many connecting rods are used in an aircraft to connect two parts and allow force to be transmitted between the two connected parts. These connecting rods may be made of metal or of composite.
In the known way, a connecting rod comprises a longilinear body, for example, cylindrical, with, at each end, a head that allows the connecting rod to be connected to an element.
From a functional standpoint, a connecting rod allows two elements to be connected while maintaining a constant distance between them and allowing force to be transmitted between the two connected elements.
Connecting rods are engineered to react forces during normal operation and also in the event of accidental dynamic loading. In the latter instance, a connecting rod does not filter out some of the energy but transmits it in full from one end to the other which means that the elements connected need to have a structure that is reinforced in the region of the connection to the connecting rod. This reinforcing of the structure leads to an increase in the amount of weight carried and therefore to an increase in the energy consumption of the aircraft.
By way of example, an aircraft engine fan is positioned in a duct connected to the rest of the structure of the nacelle by a number of connecting rods referred to as thrust rods, illustrated for example in document FR-2,806,699. Should a fan blade break, the energy stored by the blade tends to deform the duct and to spread towards the structure of the nacelle along the connecting rods.
Depending on the material used, a connecting rod can deform in the plastic domain in buckling and absorb some of the energy in the event of accidental dynamic loading.
While this type of energy absorption is possible with metal connecting rods, it is not possible in connecting rods made of composite material which are unable to deform in the plastic domain in buckling.
In addition, although this type of deformation in the plastic domain in buckling is possible when the connecting rods are made of metal, it causes a significant relative movement between the heads of the connecting rod and this is generally detrimental to the structure of the nacelle or of the aircraft.